Republican Sen. Marco Rubio of Florida wants the Senate to keep praying before lawmakers get down to business. Texas legislators, too, want their daily prayers.

And in an unexpected pew-sharing, the Obama administration has joined conservative state and federal lawmakers in urging the Supreme Court to tolerate prayers during government meetings.

“For a few minutes each morning, politics and party are set aside,” Rubio and 33 other senators advised the Supreme Court in a legal brief. “Instead of debate, senators reflect on their duty . . . mindful of the nation’s core values and their need for divine assistance in carrying out their responsibilities.”

In truth, few senators are usually present during their chaplain’s daily prayer. But on Wednesday, they’ll be paying heed as the future of such legislative prayers comes before the Supreme Court. Starting in a modest-sized city in upstate New York, the case has grown into a potential First Amendment thunderbolt.

“I think that this is such an important and interesting case; really, really important,” said Pamela Harris, a visiting professor at Georgetown University Law Center. “This is a court that’s been very receptive to the claim that there needs to be more room for religion in the public square.”

The case called Town of Greece v. Galloway, though, almost certainly won’t be a simple referendum on whether legislative prayers violate the First Amendment’s prohibition against the government establishing a religion. Prayers by political bodies, which in the United States date several centuries, seem safe.

“The reason legislative prayer is constitutional is because it’s been done since the (nation’s) founding, including by the Congress that promulgated the First Amendment,” former Solicitor General Paul Clement noted.

At the same time, the case gives the closely divided court its first opportunity in three decades to clarify the rules governing legislative prayers, potentially in a way that affects other public religious expressions, as well. Justices might resolve when public religious expressions become coercive or construed as an endorsement. They also might decide whether coercion or endorsement provides the right test for evaluating public religious expressions.

The vexing constitutional questions, as well as some decidedly one-sided politics, are underscored in the pre-argument lineups.

Eighty-five members of the House of Representatives – including six from Florida, 11 from Texas and six from North Carolina – have signed on to a brief akin to the Senate’s that endorses legislative prayers. Only 12 House members joined an opposing brief that urges tighter scrutiny, and no senators did.

Attorneys general from Texas, Idaho and 21 other states also have urged the court to support the town of Greece’s legislative prayer program. No states have taken the opposing position. Eight elected county commissions from states that include Georgia and North Carolina are on the pro-prayer side. Law professors and political scientists present, in part, the opposing view.

Greece, a town of 96,000 near Rochester, N.Y., has opened its monthly town board meetings since 1999 with prayers delivered by local clergy and volunteers. During the first nine years, every public prayer was led by a Christian.

Two residents – one a Jew, the other an atheist – sued in 2008. The two women, Susan Galloway and Linda Stephens, noted that town residents attending the board meetings for awards ceremonies, zoning actions or other reasons must sit through the prayers.

“Citizens face undeniable pressure to participate in these prayers, presenting religious minorities with the untenable choice of betraying their conscience or visibly dissenting from (the majority’s) religious norms,” attorneys for Galloway and Stephens advised the court.

Americans United for Separation of Church and State is representing the two women. The town of Greece has been assisted by Alliance Defending Freedom, which describes itself as “a servant ministry building an alliance to keep the door open for the spread of the Gospel by transforming the legal system.”

Since Galloway and Stephens sued, the town has expanded the religions represented. Nonetheless, an appellate court ruled last year that the town’s prayer program, in the eyes of a “reasonable observer,” would be “viewed as an endorsement of a particular religious viewpoint.”

Much debate will revolve around a 1983 Nebraska case in which the Supreme Court decided that opening legislative sessions with prayers didn’t violate the First Amendment. Under the ruling, called Marsh v. Chambers, legislative prayer is blocked only if the government acts with “impermissible motive” in selecting prayer-givers or if it uses the prayers to advance a particular religion or denigrate another.

The Supreme Court now might second-guess the 1983 decision, as some advocacy groups urge, such as the American Civil Liberties Union. More likely, the justices might retain at least the basics of the Marsh standard, determine whether the town of Greece met it and use the new decision to clarify how future public prayer challenges will be evaluated.

The Obama administration, for one, suggests an essentially tolerant standard that would, in the words of Solicitor General Donald Verrilli Jr., keep courts out of “the business of parsing the theological content or meaning of particular prayers.”